An impedimetric e-tongue based on CeO2-graphene oxide chemical sensors for detection of glyphosate and its potential interferents

Abstract

• Use of original CeO2/graphene oxide impedimetric sensors. • Impedimetric electronic tongue to detect glyphosate without needing redox reactions. • Sensor method with response identical to quantitative 1H NMR at 95 % confidence level. • Discrimination of glyphosate from aminomethyl phosphonic acid and N -nitroso glyphosate. • -Mechanism of detection ascribed to differences of dipole moment of analytes. Glyphosate (GLY) is the most common and widespread herbicide applied to prevent unwanted weeds. However, its detection with conventional analytical methods is a hard task. In this regard, this contribution proposes an original impedimetric electronic tongue (IET) based upon CeO 2 -graphene oxide chemical sensors and principal component analysis for easier detection of GLY. This IET was capable of detecting GLY within a linear range of concentrations, 110 to 290 nmol/L (R 2 = 0.99), showing a limit of detection of 30 nmol/L, which is far below that established by international safety regulations. This was made possible even in the presence of potential interferents, namely aminomethyl phosphonic acid and N -nitroso glyphosate. The IET performed identically to quantitative 1 H NMR at 95 % confident level. Once it does not rely on redox reactions or previous derivatization, this IET is a simpler alternative to detect and monitor GLY and its interferents in aqueous media.